As an electro-photographic type image forming apparatus, a printer including a photosensitive body and a developing cartridge configured to supply toner to the photosensitive body is known.
A conventional printer is provided with a detection device for detecting information of the developing cartridge assembled therein, for example, for detecting whether or not the cartridge is a brand new cartridge.
Japanese Patent Application Publication No. 2007-79284 discloses an integral detection structure having a detection projection and a feed electrode. The detection projection is made from an electrically conductive resin and is provided at a side surface of the developing cartridge. The projection is in abutment with an actuator in a main casing. The feed electrode is configured to abut on a feed electrode in the main casing.
The detection structure is covered by a gear cover, and is irreversibly displaceable from a new cartridge position to an old cartridge position. The detection projection and the feed electrode are accommodated in the gear cover in case of the new cartridge position, and these are exposed to an outside through an opening of the gear cover in case of the old cartridge position.